油管钢在含CO₂/H₂S高温高压水介质中的腐蚀行为及防护技术的作用

【作者】 周计明；

【导师】 刘道新；

【作者基本信息】 西北工业大学 ， 材料学， 2002， 硕士

【摘要】 利用高温高压釜实验着重研究了抗硫钢N80S与普通钢N80在模拟油田采出液中的腐蚀行为，拟找出影响油气井油套管材料腐蚀的主要影响因素及各种因素的作用程度，为油气田材料的选用提供依据，也为控制腐蚀找到理论基础。同时，利用自制的高温参比电极测试了常温常压下N80钢的CO₂腐蚀行为，为进行高温高压电化学实验奠定基础。另外，利用电化学测试技术探讨了粉末渗锌用于控制油管钢腐蚀的可行性。最后利用交流阻抗技术和动电位极化法评价了油气田中常用的一种缓蚀剂—咪唑啉，初步探讨了其缓蚀机理。 高温高压釜实验结果表明：（1）N80钢平均腐蚀速率随H₂S含量的增加表现出先增后降的非单调变化规律，而N80S钢则表现出随H₂S含量增加而单调下降的趋势。（2）随着介质中CO₂含量的增加，N80和N80S的腐蚀速率均呈增大的趋势，CO₂含量为5％时，腐蚀速率相差最大，N80腐蚀速率是N80S的2倍多。（3）随着介质中Ca²⁺、Mg²⁺离子含量的增加，N80和N80S钢的平均腐蚀速率均呈增大的趋势。（4）Cl^-浓度的影响较为复杂，两种钢表现出相同的变化趋势，随Cl^-浓度的变化表现出先增后减的趋势。利用SEM、X射线衍射等分析技术和相关理论对以上实验结果进行了分析与解释。 利用所制得的高温AgCl参比电极，进行了动电位极化法与交流阻抗技术的测试研究，结果表明，常温常压下所制备AgCl参比电极较为稳定，并达到了有关技术要求。 利用EIS和动电位测试技术评价了防止CO₂腐蚀的表面渗锌技术和缓蚀剂防护方法。结果表明，表面渗锌与加注咪唑啉类缓蚀剂可有效地防止CO₂腐蚀。更多还原

【Abstract】 Autoclave tester was used to study corrosion behavior of N80 steel and N80S steel in simulated oil well produced water contained CO2 and H2S at high temperature and high pressure. High temperature reference electrode was developed to study the CO2 corrosion behavior of N80 steel in ambient condition. Corrosion prevention methods were also studied in this paper, including the metal diffusion and inhibitor injection techniques.The results of autoclave tests shows: (1) with the H2S partial pressure increasing, the corrosion rate of N80 steel varies as a similar parabola curve, and a peak corrosion rate occurs at 3000mg/m3 H2S; whereas the corrosion rate of N80S steel decreases monotonously. (2) CO2 partial pressure affects the corrosion rate of N80 steel and N80S steel in the same way. The higher the CO2 partial pressure is, the severer the corrosion is. But the corrosion rate of N80 steel is severer than that of N80S steel. (3) with the content of Cl- increasing, the corrosion rate of N80 steel and N80S steel increase firstly and decrease after the peak corrosion rate. (4) with the content of Ca2+, Mg2+ increasing, the corrosion rate of N80 steel and N80S steel increases in the same way. SEM, X-Ray diffraction techniques were used to analysis the test results.EIS and Potentiodynamic techniques were used to detect the stability of Ag/AgCl reference electrode. The result showed that the difference between Ag/AgCl and SCE reference electrode is about 45±1mV. It met the requirement of electrochemical measurement techniques.EIS and Potentiodynamic techniques were used to evaluate the methods for preventing CO2 corrosion, including metal diffusion and inhibitor injection. The results showed that the inhibitor imidazoline and Zn diffusion treatment techniques could effectively prevent the CO2 corrosion.更多还原